1. Technical Field
The present invention relates to a head-mounted display device that is used while being mounted on the head of an observer to thereby form a virtual image in a visual field area of the observer.
2. Related Art
In recent years, there is known a head-mounted display device that is used while being mounted on the head of an observer to thereby form a virtual image in a visual field area of the observer. The head-mounted display device is called head mounted display (HMD) as well. As the HMD, there are known a transmissive HMD that enables the observer to see an external scenery while wearing the HMD device and a non-transmissive HMD that blocks the external scenery when the observer wears the HMD device. The transmissive HMD forms a virtual image in the visual field area of the observer together with the external scenery by causing an optical system or the like arranged before the eyes of the observer to reflect image light generated by a light modulation device such as a liquid crystal panel.
The observer can enjoy an image (a video) and sound anywhere while wearing the HMD device like eyeglasses. On the other hand, there is also a demand for suspension of a state in which the image (the video) and the sound are reproduced in the HMD device. Concerning such a demand, in the past, there is known a technique for enabling the observer to check the state of the outside world by suspending the image (the video) and/or the sound when the observer performs mute operation and changing a screen to a see-through state (e.g., JP-A-09-304727).
In this technique, since the display of the image (the video) is suspended when the mute operation is performed and the screen is changed to the see-through state, some time lag occurs from the mute operation until the screen changes to the see-through state.